Questions tagged [beam]
Questions about the theory and applications of structural elements designed to resist bending.
248
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Why shouldn't we use Bernoulli beam theory if deformations and rotations are large?
I was going through the basic assumptions made by Bernoulli beam theory. I realized that one of the most important assumption in this theory is that the deformations and rotations of the beams are ...
2
votes
4answers
230 views
Is bending moment along a beam independent of the cross sectional area of the beam?
We know this that if the a cantilever beam (of any cross section) is fixed at one end and a transverse force is applied on the other, then it will bend. However, we just casually assume that the ...
0
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1answer
39 views
Why am I seeing a moment reaction at the supports for these beams in FEM?
Please observe the Finite Element model below, in ANSYS WorkBench, (Remote force behavior = Deformable).
Also, please take a lot at the force and moment reactions at the fixed supports.
I couldn't ...
0
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4answers
77 views
When we replace supports distributed reaction by point reaction in thin beams, is that considered an application of Saint-Venant principle?
I read about Saint-Venant principle which is about the effect of replacing forces by equivalent forces system that effect on the same small region of a rigid body, all examples I come across are on ...
0
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2answers
44 views
Help with understanding bending moment diagram of a frame structure
I have an exercise where I should calculate and draw a bending moment diagram for a frame structure. The frame structure is similar to the one below, image taken from http://structx.com:
I would like ...
0
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2answers
53 views
Calculate shear and deflection for simply supported beam on different support height (like a staircase)?
I’m trying to calculate the beam deflection for an inclined beam. It’s only connected to floors (and not walls). The beam is a monorail and I want to test different shapes (tubes and I-beams).
Plenty ...
1
vote
2answers
59 views
Shear and Bending Moment
A square tube is slid into a larger square tube. If a load is applied to the end of the inner tube, I would think that inner tube would mainly contact the outer tube in two locations as the load is ...
0
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1answer
24 views
Ways to stiffen a HSS profile?
I have an issue with a post that’s deflecting a little bit too much. Picture a 10 foot HSS c-channel section, used vertically as a post. Web/flange 4.5 x 1.75 @ 3/16 thick.
Clients (friends) insisted ...
0
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1answer
53 views
Utilizing symmetry in statics problem
I am given the structure below, and supposed to find the forces occuring in $A, F, E, D, C$ and $B$. The task hints of using symmetry, as several forces are equal in magnitude.
Supposedly, $A=B$, and ...
0
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1answer
74 views
Angular momentum of a multi-body system
I'm trying to compute the total angular momentum of a 3D multi-body, pendulum-like (as in, each body is connected to another one), mechanical system. Let us consider, for a simpler case, a 2D double ...
2
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2answers
50 views
strongest way to join ibeams at angle
I have a stock of surplus i-beams (aluminum) and am trying to build a structure where they are not always parallel. I understand i-beam is designed to be aligned vertically and optimized for strength ...
0
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2answers
24 views
Stresses due to combined loadings in a bent shaft supported at both ends
I was hoping someone might be able to help clarify where I might be going wrong with this question. I am being asked to essentially determine the maximum normal and shear stresses at the rigid support ...
1
vote
1answer
46 views
How to find the reaction at the pinned support A as shown in the picture? [closed]
Please help me solve the problem. I need to know the reactions at A for both the cases as shown. Please note that E is a roller, D is a pin support , B is an internal hinge and A for case 2 is a fixed ...
0
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3answers
89 views
Why is my FEM analysis producing unusually-large stress results?
This is my first time performing an FEM analysis, and I'm using the Ansys Workbench and Mechanical software.
My situation is pretty straightforward--it's a straight beam that is fixed at one end and ...
2
votes
2answers
65 views
How to calculate the required prestressed jacking pressure to apply to a pre-tension concrete beam?
How does the fabricant of prestressed pre-tensioned beams calculate the equivalent pressure in the hydraulic jack (in bars) to the design prestress force (in kN)? Are there factors to multiply like a ...
2
votes
1answer
86 views
Is the calculated shear strain in a beam, engineering strain or tensorial strain?
Recently I came across a FEM code of a linear deformation beam element, and it made me wonder what is the correct relation between shear stress and shear strain in a beam element.
In the beam element ...
1
vote
1answer
77 views
Finding Safety Factor for Plastic Snap Fit Cantilever
I'm trying to get a safety factor of $n\geq2$ for the root of my snap fit beam (pic at bottom of the post).
I have gone through the calculations to get the SF at the root's edge from the geometric ...
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0answers
62 views
On rectangular section beam properties of plate stiffeners
I am trying to understand the expression of the vertical dynamic stiffness $K_T$ and the rotational dynamic stiffness $K_r$ which appears in this paper where they consider a semi-infinite plate ...
3
votes
3answers
465 views
What are the units used in beam bending equations? Do they matter?
I was just wondering whether or not the standard beam bending equations worked for all units. E.g. imperial and metric etc.
From what I'm guessing it shouldn't really, since once we plug everything in ...
0
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2answers
94 views
Can a beam be too short to experience bending stress?
The question in the title says it all. I've got a a configuration where I'm using a bolt to support a load. The way its set up, the bolt will have a very short cantilever on it. When I calculate the ...
1
vote
1answer
68 views
Comparison of Shear Stress obtained from thin-walled beam theory and Timoshenko beam theory
I am studying the book "Structural Analysis with Applications to Aerospace Structures" by Craig. In Chapter 8 titled "Thin-Walled Beams", the authors derived the governing ...
0
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1answer
38 views
How to determine beam deflection with this unusual configuration (diagram attached)
So I've got a support system shown here in the attached image. Comparing configuration "A" to "B" it seems intuitive that "A" could support a larger load. The stubs are ...
2
votes
3answers
96 views
Is an axial force applied at the centre of a beam considered a compressive force, tensile force, or both?
I was looking through some course notes and realized that I never fully understood this concept. So, looking at the diagram below we can see that there is a 20kN axial force being applied in-between ...
1
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2answers
43 views
Where to place air, water and electric cables in a composite beam [closed]
If water, gas and electrical cables have to pass through three (3) openings
provided in the cross section shown in Figure 2, with tangible and scientific
arguments specify the adequate opening for ...
0
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2answers
182 views
Calculating the von mises stress in a 3D beam when given stresses and moments on both ends
I want to calculate the von mises stress in a given structural member. I want to generate a von-mises plot from this data.
The forces are according to the local coordinate system of the beam. Also, I ...
0
votes
1answer
33 views
Calculating the load on the end of a beam
We ordered a really nice light for our dinner table and ordered a special "lightswing" seperatly.
The light that we ordered however is heavier than the 'lightswing' is rated for.
Please see ...
0
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0answers
40 views
How to use standard aluminium extrusions
How to use standard aluminum extrusions and accessories at Solidworks? I believe there are some libraries, but I don't know how to click or download them. Would you please teach me how to do it? Thank ...
0
votes
2answers
84 views
Find out the forces in members (as mentioned in the figure) of the truss by method of sections [closed]
I'm trying to find the forces in every member. But having a hard time resolving it. The Problem is to be solved by the Method of Sections of Truss.
2
votes
1answer
72 views
How to design an enclosure around the load cell (Beam type)?
Hardware and Electronics Used: Arduino UNO, HX711 ADC Load cell amplifier, Load Cell (2Kg);
Currently, I am working on a project which requires me to put load cell along with the other circuitry in an ...
3
votes
3answers
147 views
Fun Force Problem - Basic Structure of Two beams supporting weight
I'm very new to engineering and thought I'd start with some basic problems and test them out with my own constructions! I've come up with this fun problem and would love some help solving it.
Say you ...
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0answers
22 views
Adding tension to a model of a Timoshenko beam?
I am interested in modeling a Timoshenko beam: https://en.wikipedia.org/wiki/Timoshenko%E2%80%93Ehrenfest_beam_theory
However, I would also like to add tension to the beam so that it can vibrate like ...
0
votes
1answer
68 views
How to calculate reaction moments and forces in a fixed axle with multiple point loads?
I need to calculate the maximum moment and reaction forces in an axle with both sides fixed in bearings, the axle is 1010mm long and has downwards forces of:
236kN at 403mm
86kN at 499mm
32kN at ...
0
votes
1answer
28 views
Diagrams of forces and moments of a statically determinate structure
I'm having difficulties with calculating the distribution of forces and moments in a statically determinate structure shown below.
I'm especially confused about the arc part. Will there be only ...
1
vote
5answers
123 views
Exactly what makes steel-concrete composite beam better than pure steel?
A composite action beam may have a concrete section the top, carrying the compression load, and steel at the bottom, carrying tension.
But I have always thought that concrete had lower strength for a ...
1
vote
3answers
81 views
How many support beams/rods needed for a firewood storage cabinet
I am building a firewood storage cabinet which should support around 100-150 kg of firewood.
The cabinet is made out of wooden boards (...
0
votes
3answers
309 views
Why is it said that the flange of an I beam carries most of the moment?
It is often said for I beams that the flange carries most of the moment subjected to the beam, while the web carries most of the shear force. The latter is obvious from pictures like above, showing ...
0
votes
1answer
60 views
Cantilever beam
I want to design a cantilever addition. Over the driveway so I can't add supports.
I want to use the calculator here
https://calcresource.com/moment-of-inertia-rect.html
But I'm having trouble ...
1
vote
1answer
29 views
If an airfoil underwent horizontal loading, would it stiffen the airfoil? [closed]
I am designing a wing for a Vertical Takeoff and Landing aircraft. I am trying to choose a wingtip winglet for my aircraft. One of the option is a aft-swept wingtip winglet. However, this structure ...
0
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1answer
60 views
Boundary conditions for a cantilevered Timoshenko Beam
I am trying to find out the boundary conditions for above given Timoshenko beam. The boundary conditions that I have derived are
$x_1 = 0$
$$ \overline{u}_2^L = 0 $$
$$ \phi_3^L = 0 $$
$x_1 = \...
0
votes
4answers
116 views
Deflection of a fixed-fixed pvc pipe under self weight
I would like to start by saying I am not an engineer, so I apologize if this question seems simpleminded.
I am making a manual tarp reel from pvc pipe, and I am trying to decided whether to use ...
0
votes
1answer
79 views
How to calculate the force of a cantilever beam at a given point of deflection?
I have put together a simple cantilever beam using finite difference modeling according to the following standard wave equation
$$ρAy_{tt} = -EIy_{xxxx}$$
where $ρ$ is density, $A$ is cross sectional ...
1
vote
1answer
73 views
Simple cantilever beam deflection - what is the simplest way to add a damper?
I am looking at a simple cantilever beam deflection:
I understand the general expression for deflection/force would be:
$$y_s = \frac{Fx_s^3}{3EI}$$
$$F_p = \frac{3y_sEI}{x_s^3}$$
If you were going ...
1
vote
2answers
147 views
Multiple varying cross section beam with uniform loads
I have the following cantilever beam problem where I need to find the deflection of the tip at P.
I tried to compute the deflection of the beam using Castignliano' s theorem as described in this ...
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3answers
88 views
Statically determinate system
The exercise is taken from linear algebra and its applications, prof. G. Strang
Exercise 2.4.8 Truss
I have already found that: m=n=8 → system is statically determinate, therefore solvable by ...
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0answers
13 views
double integration of continues beam to find the deflection at mid span [duplicate]
does any one know how to derive the deflection equation of a continues beam of three span of equal length and equal UDL load
some of the steps of this explanation I didn't understand it Here's a link ...
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0answers
42 views
Continues beam deflection
does any one know how to derive the deflection equation of a continues beam of three span of equal length and equal UDL load
Here's a link
these two pictures shows my tries to solve the question
1
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1answer
39 views
Derivaiton of maximum deflection of a cantilever beam with intermediate load
I am trying to derive the maximum deflection of a cantilever beam. L is the length of the beam and a is the where force is applied.
For the case 0<x<a, I use the method below and it gives me the ...
1
vote
3answers
147 views
How can deflection and spring constant of cantilever beam stack be calculated?
How can I calculate some properties of a stack of 2 bonded cantilever beams like in the image? Especially I am interested in the spring constant and deflection with force on random locations. However, ...
0
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0answers
29 views
Design of T-Beam
Please design a T-beam section size such that hf ≥ 125 mm, bw ≥ 200 mm, be ≥ 500 mm, d ≥ 300 mm, the concrete f'c strength is 25 MPa; the calculated concrete shear strength Vc that can be provided is ...
1
vote
1answer
134 views
How to check if bending moment diagram is correctly drawn
EDIT: I will state my test problem description and then my solution. But before that, I would like to apprise you of the absence of the actual description given during test (which happened in Zoom and ...
